1/2 hour after bringing the phone home, I now have an unlocked E4 that I have tested with my AT&T, T-Mobile, and Mint SIM cards. Everything works as it should on all carriers. Not sure about WiFi calling because I don't use that feature on any phone.

This is a great phone. I used to buy flagships, now I buy midrange devices, currently have a BlackBerry KEYone. They do everything I need. I don't play games on my phone nor do I watch videos very frequently and I have never been a part of Facebook/Instagram/Twitter/etc. My phones are used as a business/communication tool. This E4 does everything I need to do well and the battery is fantastic.

This is a good buy. Great form factor, pretty much stock Android 7.1.1 out of the box, and 2GB of RAM.